00:01
Okay, so let's look at this problem number 77.
00:04
Okay, we have a plane, and this airplane's speed is 150 miles per hour, okay? and we also, we want to sit on this plane and take a three -hour sizing trip.
00:21
Okay, so our direction is fly to the north as far as possible, and then return to the back, return to the original point at the end of the three hours.
00:34
So first we know that how far we should go north.
00:39
Okay, if we have, you know, we is facing this wind and it blows from the north and the speed is 30 miles per hour.
00:47
Okay, so let's see.
00:56
Okay, so let's suppose that we should we should take x of time.
01:07
To fly to north.
01:13
Okay, so which means we take x hours to fly to north and we take 3 minus x, you know, to travel back, right? to return or to return.
01:39
Okay, so we have 150 minus 30 times x, okay, equals to 150.
01:52
Plus 30 times x, uh, 3 minus x, sorry, 3 minus x...